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Abstract

THIS book gives, in a connected form, a summary of the development of the vegetable kingdom in geological time. Though likely to be of use to geologists and botanists, the treatment is sufficiently popular to be intelligible to the general reader. The floras of the successive geological formations are treated of in turn, from the oldest rocks down to comparatively recent times. The two longest chapters in the book are devoted to the vegetation of the Devonian and Carboniferous ages respectively, much of the matter here traversed having formed the subject of numerous scientific memoirs by the author. In the body of the work, accounts of the morphology and minute anatomy of the various plant-remains are given, with speculations as to their affinities, and in many cases restorations are attempted, illustrated by figures. The more special details as to classification, &c., are wisely placed in small type as a series of Jiotes at the end of each chapter. The last chapter in the book consists of an interesting essay on the general laws of origin and migrations of plants. Many of the woodcuts leave much to be desired, more especially those dealing with histological subjects. These are, for the most part, scrappy and insufficiently described, and convey little to the mind. Comparisons between fossil remains and recent plants are often rendered valueless by strange inaccuracies as to the morphological value of the parts so compared. Thus the leaves of Marsilea (pp. 60 and 67) are described as being in whorls and cuneate in form, and in Azolla and Salvinia the leaves are “frondose and more or less pinnate in their arrangement.” Spenophyllum, which possesses wedge-shaped leaves arranged in verticels on the stem, is set down as of probable Rhizocarpian affinity, on this mistaken comparison between its leaves and the leaflets of Marsilea! Much confusion also arises from, a careless use of the terms sporocarp, sporangium, macro- and micro-spore, antheridium, &c., in connection with certain small bodies found in the Erian and Carboniferous beds, and conceived by the author to be the reproductive bodies of a rich, then-existing Rhizocarpian flora. Though there are many points in which palæobotanists may not be at one with the author—such as the reference of so many Palaeozoic forms to Rhizocarps—the volume will be of service, especially to those to whom the larger treatises are not available.

The Geological History of Plants.

By Sir J. W. Dawson, &c. 8vo, pp. 290. With Illustrations. “International Scientific Series.” (London: Kegan Paul, Trench, and Co., 1888.)